diff --git a/backend/prisma/migrations/20261017_004_deces_sans_date/migration.sql b/backend/prisma/migrations/20261017_004_deces_sans_date/migration.sql
new file mode 100644
index 0000000..14f6e2c
--- /dev/null
+++ b/backend/prisma/migrations/20261017_004_deces_sans_date/migration.sql
@@ -0,0 +1,2 @@
+-- Personne décédée sans date connue (issue #77)
+ALTER TABLE "persons" ADD COLUMN "isDeceased" BOOLEAN NOT NULL DEFAULT false;
diff --git a/backend/prisma/schema.prisma b/backend/prisma/schema.prisma
index 4ce8cf7..098b07e 100644
--- a/backend/prisma/schema.prisma
+++ b/backend/prisma/schema.prisma
@@ -214,6 +214,8 @@ model Person {
   birthName          String?
   birthDate          DateTime?
   deathDate          DateTime?
+  // Décédé(e) sans date connue (issue #77) : vrai seulement quand deathDate est vide
+  isDeceased         Boolean   @default(false)
   birthPlace         String?
   // Précision d'une date importée (« vers », « avant », « entre »…) et sa borne de fin pour « entre … et … »
   birthDatePrecision String?
diff --git a/backend/src/routes/contributions.ts b/backend/src/routes/contributions.ts
index 4facfe3..126c63f 100644
--- a/backend/src/routes/contributions.ts
+++ b/backend/src/routes/contributions.ts
@@ -73,6 +73,7 @@ const personCreateSchema = z.object({
   birthName: z.string().max(120).optional().nullable(),
   birthDate: z.string().regex(isoDateRegex).optional().nullable(),
   deathDate: z.string().regex(isoDateRegex).optional().nullable(),
+  isDeceased: z.boolean().optional(),
   birthPlace: z.string().max(200).optional().nullable(),
   profession: z.string().max(200).optional().nullable(),
   region: z.string().max(120).optional().nullable(),
@@ -88,6 +89,7 @@ const personUpdateSchema = z
     birthName: z.string().max(120).optional().nullable(),
     birthDate: z.string().regex(isoDateRegex).optional().nullable(),
     deathDate: z.string().regex(isoDateRegex).optional().nullable(),
+    isDeceased: z.boolean().optional(),
     birthPlace: z.string().max(200).optional().nullable(),
     profession: z.string().max(200).optional().nullable(),
     region: z.string().max(120).optional().nullable(),
@@ -378,6 +380,7 @@ async function applyContributionChange(
           birthName: toTrimmedStringOrNull(parsed.data.birthName),
           birthDate: toDateOrNull(parsed.data.birthDate),
           deathDate: toDateOrNull(parsed.data.deathDate),
+          isDeceased: !parsed.data.deathDate && Boolean(parsed.data.isDeceased),
           birthPlace: toTrimmedStringOrNull(parsed.data.birthPlace),
           profession: toTrimmedStringOrNull(parsed.data.profession),
           region: toTrimmedStringOrNull(parsed.data.region),
@@ -434,6 +437,7 @@ async function applyContributionChange(
           birthName: parsed.data.birthName !== undefined ? toTrimmedStringOrNull(parsed.data.birthName) : undefined,
           birthDate: nextDates.birthDate,
           deathDate: nextDates.deathDate,
+          isDeceased: nextDates.deathDate ? false : parsed.data.isDeceased,
           birthPlace: parsed.data.birthPlace !== undefined ? toTrimmedStringOrNull(parsed.data.birthPlace) : undefined,
           profession: parsed.data.profession !== undefined ? toTrimmedStringOrNull(parsed.data.profession) : undefined,
           region: parsed.data.region !== undefined ? toTrimmedStringOrNull(parsed.data.region) : undefined,
@@ -830,6 +834,7 @@ async function snapshotEntity(
         birthName: true,
         birthDate: true,
         deathDate: true,
+        isDeceased: true,
         birthPlace: true,
         profession: true,
         region: true,
diff --git a/backend/src/routes/gedcom.ts b/backend/src/routes/gedcom.ts
index 4a33083..ed675a9 100644
--- a/backend/src/routes/gedcom.ts
+++ b/backend/src/routes/gedcom.ts
@@ -477,6 +477,9 @@ export const gedcomRoutes: FastifyPluginAsync = async (app) => {
         if (deathDate) lines.push(`2 DATE ${deathDate}`)
         if (person.deathPlace) lines.push(`2 PLAC ${oneLine(person.deathPlace)}`)
         pushNotesAndSources(lines, 2, deathDetails)
+      } else if (person.isDeceased) {
+        // Décédé(e) sans rien d'autre : la forme courte de la norme
+        lines.push('1 DEAT Y')
       }
 
       // Le champ « profession » s'écrit seulement s'il n'est pas déjà un des métiers datés
@@ -692,6 +695,8 @@ export const gedcomRoutes: FastifyPluginAsync = async (app) => {
             sex,
             birthDate,
             deathDate,
+            // « 1 DEAT Y » ou un décès sans date : décédé(e), date inconnue
+            isDeceased: Boolean(deatNode) && !deathDate,
             birthPlace,
             profession,
             notes,
diff --git a/backend/src/routes/trees.ts b/backend/src/routes/trees.ts
index dce079b..de1805b 100644
--- a/backend/src/routes/trees.ts
+++ b/backend/src/routes/trees.ts
@@ -89,6 +89,7 @@ const createPersonSchema = z.object({
   birthName: z.string().max(120).optional().nullable(),
   birthDate: z.string().regex(isoDateRegex).optional().nullable(),
   deathDate: z.string().regex(isoDateRegex).optional().nullable(),
+  isDeceased: z.boolean().optional(),
   birthPlace: z.string().max(200).optional().nullable(),
   profession: z.string().max(200).optional().nullable(),
   region: z.string().max(120).optional().nullable(),
@@ -104,6 +105,7 @@ const patchPersonSchema = z
     birthName: z.string().max(120).optional().nullable(),
     birthDate: z.string().regex(isoDateRegex).optional().nullable(),
     deathDate: z.string().regex(isoDateRegex).optional().nullable(),
+    isDeceased: z.boolean().optional(),
     birthPlace: z.string().max(200).optional().nullable(),
     profession: z.string().max(200).optional().nullable(),
     region: z.string().max(120).optional().nullable(),
@@ -1310,6 +1312,8 @@ export const treeRoutes: FastifyPluginAsync = async (app) => {
         birthName: toTrimmedStringOrNull(payload.data.birthName),
         birthDate: toDateOrNull(payload.data.birthDate),
         deathDate: toDateOrNull(payload.data.deathDate),
+        // Une date de décès dit déjà que la personne est décédée : le drapeau ne sert que sans date
+        isDeceased: !payload.data.deathDate && Boolean(payload.data.isDeceased),
         birthPlace: toTrimmedStringOrNull(payload.data.birthPlace),
         profession: toTrimmedStringOrNull(payload.data.profession),
         region: toTrimmedStringOrNull(payload.data.region),
@@ -1366,6 +1370,7 @@ export const treeRoutes: FastifyPluginAsync = async (app) => {
       birthName?: string | null
       birthDate?: Date | null
       deathDate?: Date | null
+      isDeceased?: boolean
       birthPlace?: string | null
       profession?: string | null
       region?: string | null
@@ -1395,6 +1400,14 @@ export const treeRoutes: FastifyPluginAsync = async (app) => {
       data.deathDate = toDateOrNull(payload.data.deathDate)
     }
 
+    if (payload.data.isDeceased !== undefined) {
+      data.isDeceased = payload.data.isDeceased
+    }
+    // Avec une date de décès, le drapeau « sans date » n'a plus lieu d'être
+    if (data.deathDate) {
+      data.isDeceased = false
+    }
+
     if (payload.data.birthPlace !== undefined) {
       data.birthPlace = toTrimmedStringOrNull(payload.data.birthPlace)
     }
diff --git a/backend/src/utils/graph-payload.ts b/backend/src/utils/graph-payload.ts
index 4ae8370..78a4a04 100644
--- a/backend/src/utils/graph-payload.ts
+++ b/backend/src/utils/graph-payload.ts
@@ -11,6 +11,7 @@ export type GraphPayload = {
     birthName: string | null
     birthDate: string | null
     deathDate: string | null
+    isDeceased: boolean
     birthPlace: string | null
     profession: string | null
     region: string | null
@@ -85,6 +86,7 @@ export function buildGraphPayload(
         birthName: person.birthName,
         birthDate: formatDate(person.birthDate),
         deathDate: formatDate(person.deathDate),
+        isDeceased: Boolean(person.isDeceased) && !person.deathDate,
         birthPlace: person.birthPlace,
         profession: person.profession,
         region: person.region,
diff --git a/backend/test/api-routes.test.ts b/backend/test/api-routes.test.ts
index d603079..5f9b606 100644
--- a/backend/test/api-routes.test.ts
+++ b/backend/test/api-routes.test.ts
@@ -487,7 +487,7 @@ describe('Graph routes', () => {
     prismaMock.tree.findFirst.mockResolvedValue({ id: 'tree-1', name: 'Ragot', rootPersonId: null })
     prismaMock.person.findMany.mockResolvedValue([
       { ...base, id: 'p-1', firstName: 'Louis', lastName: 'Ragot', sex: 'male', birthDate: new Date('1879-01-01T00:00:00Z'), birthDatePrecision: 'about', birthPlace: 'La Roche-sur-Yon', deathDate: new Date('1950-05-02T00:00:00Z'), deathPlace: 'Nantes', nickname: 'Loulou', profession: 'Instituteur' },
-      { ...base, id: 'p-2', firstName: 'Marie', lastName: 'Bodin', sex: 'female', birthDate: null, birthDatePrecision: null, birthPlace: null },
+      { ...base, id: 'p-2', firstName: 'Marie', lastName: 'Bodin', sex: 'female', birthDate: null, birthDatePrecision: null, birthPlace: null, isDeceased: true },
       { ...base, id: 'p-3', firstName: 'Jean', lastName: 'Ragot', sex: 'male', birthDate: null, birthDatePrecision: null, birthPlace: null },
     ])
     prismaMock.union.findMany.mockResolvedValue([
@@ -513,6 +513,8 @@ describe('Graph routes', () => {
     expect(text).toContain('1 OCCU Instituteur\n2 DATE FROM 1900 TO 1935')
     expect(text.match(/1 OCCU/g)).toHaveLength(1)
     expect(text).toContain('2 PEDI adopted')
+    // Décédée sans date (issue #77) : la forme courte de la norme
+    expect(text).toContain('1 NAME Marie /Bodin/\n1 SEX F\n1 DEAT Y\n')
 
     const roots = parseGedcom(text)
     const records = indexGedcomRecords(roots)
@@ -631,6 +633,24 @@ describe('Graph routes', () => {
   })
 })
 
+describe('Décès sans date (issue #77)', () => {
+  it('marque décédé sans date, et une date de décès retire le drapeau', async () => {
+    const app = createApp()
+    const token = await createUserToken(app)
+    const patch = (payload: object) => app.inject({ method: 'PATCH', url: '/trees/tree-1/persons/person-1', headers: { authorization: `Bearer ${token}` }, payload })
+
+    expect((await patch({ isDeceased: true })).statusCode).toBe(200)
+    expect(prismaMock.person.updateMany.mock.calls.at(-1)[0].data).toMatchObject({ isDeceased: true })
+
+    expect((await patch({ deathDate: '1950-01-01', isDeceased: true })).statusCode).toBe(200)
+    expect(prismaMock.person.updateMany.mock.calls.at(-1)[0].data).toMatchObject({ isDeceased: false, deathDate: new Date('1950-01-01T00:00:00.000Z') })
+
+    expect((await patch({ isDeceased: false, deathDate: null })).statusCode).toBe(200)
+    expect(prismaMock.person.updateMany.mock.calls.at(-1)[0].data).toMatchObject({ isDeceased: false, deathDate: null })
+    await app.close()
+  })
+})
+
 describe('Moments de l’onglet Vie', () => {
   it('un admin ajoute un moment avec deux souvenirs, le modifie sans changer son type, le supprime', async () => {
     const app = createApp()
diff --git a/frontend/src/App.jsx b/frontend/src/App.jsx
index 44334dd..07f2d45 100644
--- a/frontend/src/App.jsx
+++ b/frontend/src/App.jsx
@@ -241,6 +241,7 @@ function buildContributionChangesFromDraft(draft = {}) {
         birthName: person.birthName ? String(person.birthName).trim() : null,
         birthDate: person.birthDate || null,
         deathDate: person.deathDate || null,
+        isDeceased: !person.deathDate && Boolean(person.isDeceased),
       },
     })
 
@@ -289,7 +290,10 @@ function buildContributionChangesFromDraft(draft = {}) {
     if (Object.prototype.hasOwnProperty.call(source, 'region')) after.region = (source.region || '').trim() || null
     if (Object.prototype.hasOwnProperty.call(source, 'nationality')) after.nationality = (source.nationality || '').trim() || null
     if (Object.prototype.hasOwnProperty.call(source, 'note')) after.notes = source.note || null
-    if (Object.prototype.hasOwnProperty.call(source, 'isAlive') && source.isAlive === true) after.deathDate = null
+    if (Object.prototype.hasOwnProperty.call(source, 'isAlive')) {
+      if (source.isAlive === true) after.deathDate = null
+      after.isDeceased = source.isAlive === false
+    }
 
     if (Object.keys(after).length > 0) {
       changes.push({
@@ -1073,6 +1077,7 @@ function App() {
             birthName: formData.birthName || null,
             birthDate: formData.birthDate || null,
             deathDate: formData.deathDate || null,
+            isDeceased: Boolean(formData.isDeceased),
             relations: (formData.relations || []).map((rel) => ({ type: rel.type, personId: rel.personId })),
             siblingParentLinks,
           },
@@ -1098,6 +1103,7 @@ function App() {
           birthName: formData.birthName,
           birthDate: formData.birthDate,
           deathDate: formData.deathDate,
+          isDeceased: Boolean(formData.isDeceased),
         },
         auth.userAuth.token
       )
@@ -1230,7 +1236,10 @@ function App() {
           if (Object.prototype.hasOwnProperty.call(rawChanges, 'profession')) payload.profession = (rawChanges.profession || '').trim() || null
           if (Object.prototype.hasOwnProperty.call(rawChanges, 'region')) payload.region = (rawChanges.region || '').trim() || null
           if (Object.prototype.hasOwnProperty.call(rawChanges, 'nationality')) payload.nationality = (rawChanges.nationality || '').trim() || null
-          if (Object.prototype.hasOwnProperty.call(rawChanges, 'isAlive') && rawChanges.isAlive === true) payload.deathDate = null
+          if (Object.prototype.hasOwnProperty.call(rawChanges, 'isAlive')) {
+            if (rawChanges.isAlive === true) payload.deathDate = null
+            payload.isDeceased = rawChanges.isAlive === false
+          }
           if (Object.prototype.hasOwnProperty.call(rawChanges, 'note')) payload.notes = rawChanges.note || null
 
           if (Object.keys(payload).length > 0) {
@@ -1510,8 +1519,13 @@ function App() {
         if (Object.prototype.hasOwnProperty.call(changes, 'region')) localPerson.region = changes.region || null
         if (Object.prototype.hasOwnProperty.call(changes, 'nationality')) localPerson.nationality = changes.nationality || null
         if (Object.prototype.hasOwnProperty.call(changes, 'note')) localPerson.note = changes.note || null
-        if (Object.prototype.hasOwnProperty.call(changes, 'isAlive') && changes.isAlive === true) {
-          localPerson.deathYear = null
+        if (Object.prototype.hasOwnProperty.call(changes, 'isAlive')) {
+          if (changes.isAlive === true) {
+            localPerson.deathYear = null
+            localPerson.deathDate = null
+          }
+          localPerson.isAlive = changes.isAlive === true
+          localPerson.isDeceased = changes.isAlive === false && !localPerson.deathYear
         }
         tree.setSelectedPerson({ ...localPerson })
       }
@@ -1532,7 +1546,10 @@ function App() {
     if (Object.prototype.hasOwnProperty.call(changes, 'profession')) payload.profession = (changes.profession || '').trim() || null
     if (Object.prototype.hasOwnProperty.call(changes, 'region')) payload.region = (changes.region || '').trim() || null
     if (Object.prototype.hasOwnProperty.call(changes, 'nationality')) payload.nationality = (changes.nationality || '').trim() || null
-    if (Object.prototype.hasOwnProperty.call(changes, 'isAlive') && changes.isAlive === true) payload.deathDate = null
+    if (Object.prototype.hasOwnProperty.call(changes, 'isAlive')) {
+      if (changes.isAlive === true) payload.deathDate = null
+      payload.isDeceased = changes.isAlive === false
+    }
     if (Object.prototype.hasOwnProperty.call(changes, 'note')) payload.notes = changes.note || null
 
     if (Object.keys(payload).length > 0) {
diff --git a/frontend/src/components/AddPersonPanel.css b/frontend/src/components/AddPersonPanel.css
index 9db624c..007f39c 100644
--- a/frontend/src/components/AddPersonPanel.css
+++ b/frontend/src/components/AddPersonPanel.css
@@ -104,3 +104,10 @@
   .add-person-panel, .add-person-panel--open { transform: none; transition: opacity 180ms ease, visibility 0s linear 180ms; }
   .add-person-panel--open { transition: opacity 180ms ease, visibility 0s; }
 }
+
+/* Décédé(e) sans date connue (issue #77) */
+.apn-deceased { display: inline-flex; align-items: center; gap: 7px; margin-top: 6px; font: 400 13px var(--pz-sans); color: var(--pz-ink-2); cursor: pointer; }
+.apn-deceased input { width: 15px; height: 15px; accent-color: var(--pz-a500); }
+
+/* Colonnes alignées en haut : la case « décédé(e) » sous le décès ne décale pas la naissance */
+.apn-row { align-items: start; }
diff --git a/frontend/src/components/AddPersonPanel.jsx b/frontend/src/components/AddPersonPanel.jsx
index f0f3ef1..b23dc40 100644
--- a/frontend/src/components/AddPersonPanel.jsx
+++ b/frontend/src/components/AddPersonPanel.jsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useRef } from 'react'
+import DateField from './DateField.jsx'
 import { UserPlus, X, Search, ChevronDown } from 'lucide-react'
 import './AddPersonPanel.css'
 import PzBusy from './PzBusy.jsx'
@@ -35,6 +36,10 @@ function AddPersonPanel({ visible, persons = [], loading = false, error = '', on
   const [birthName, setBirthName] = useState('')
   const [birthDate, setBirthDate] = useState('')
   const [deathDate, setDeathDate] = useState('')
+  // Décédé(e) sans date connue (issue #77)
+  const [isDeceased, setIsDeceased] = useState(false)
+  // Les champs de date gardent leur texte : on les recrée après chaque ajout
+  const [dateFieldsKey, setDateFieldsKey] = useState(0)
   const [relations, setRelations] = useState([])
   const [relationSearch, setRelationSearch] = useState('')
   const [relationDropdownOpen, setRelationDropdownOpen] = useState(false)
@@ -88,6 +93,8 @@ function AddPersonPanel({ visible, persons = [], loading = false, error = '', on
       setBirthName('')
       setBirthDate('')
       setDeathDate('')
+      setIsDeceased(false)
+      setDateFieldsKey((k) => k + 1)
       setRelations([])
       setTouched({})
       setJustAdded(false)
@@ -134,6 +141,7 @@ function AddPersonPanel({ visible, persons = [], loading = false, error = '', on
       birthName: birthName.trim() || null,
       birthDate: birthDate || null,
       deathDate: deathDate || null,
+      isDeceased: !deathDate && isDeceased,
       relations,
     })
   }
@@ -173,7 +181,7 @@ function AddPersonPanel({ visible, persons = [], loading = false, error = '', on
 
       <form className="apn-form" onSubmit={handleSubmit}>
         <div className="apn-scroll">
-          <div className="pz-row2">
+          <div className="pz-row2 apn-row">
             <div className="pz-field">
               <label htmlFor="ap-firstName">{t('Prénom')}</label>
               <input
@@ -217,14 +225,20 @@ function AddPersonPanel({ visible, persons = [], loading = false, error = '', on
             />
           </div>
 
-          <div className="pz-row2">
+          <div className="pz-row2 apn-row">
             <div className="pz-field">
               <label htmlFor="ap-birthDate">{t('Naissance')}</label>
-              <input id="ap-birthDate" type="date" value={birthDate} onChange={(e) => setBirthDate(e.target.value)} />
+              <DateField key={`b-${dateFieldsKey}`} id="ap-birthDate" value={birthDate} onChange={setBirthDate} />
             </div>
             <div className="pz-field">
               <label htmlFor="ap-deathDate">{t('Décès')}</label>
-              <input id="ap-deathDate" type="date" value={deathDate} onChange={(e) => setDeathDate(e.target.value)} />
+              <DateField key={`d-${dateFieldsKey}`} id="ap-deathDate" value={deathDate} onChange={setDeathDate} />
+              {!deathDate && (
+                <label className="apn-deceased">
+                  <input type="checkbox" checked={isDeceased} onChange={(e) => setIsDeceased(e.target.checked)} />
+                  {t('Décédé(e), date inconnue')}
+                </label>
+              )}
             </div>
           </div>
 
diff --git a/frontend/src/components/DateField.jsx b/frontend/src/components/DateField.jsx
new file mode 100644
index 0000000..a41ef4f
--- /dev/null
+++ b/frontend/src/components/DateField.jsx
@@ -0,0 +1,30 @@
+import { useState } from 'react'
+import { t } from '../i18n/index.js'
+import { dateToInputText, parseDateInput } from '../utils/dateInput.js'
+
+// Champ de date de la fiche : une année seule ou une date complète (issue #77). Le texte tapé reste tel
+// quel ; la valeur ne remonte qu'une fois comprise, sinon le champ le signale sans rien enregistrer.
+export default function DateField({ id, value, onChange, placeholder, className = '' }) {
+  const [text, setText] = useState(() => dateToInputText(value))
+  const invalid = parseDateInput(text) === undefined
+
+  return (
+    <span className="pz-date">
+      <input
+        id={id}
+        type="text"
+        inputMode="numeric"
+        className={className}
+        value={text}
+        placeholder={placeholder || t('Année ou date')}
+        aria-invalid={invalid || undefined}
+        onChange={(e) => {
+          setText(e.target.value)
+          const parsed = parseDateInput(e.target.value)
+          if (parsed !== undefined) onChange(parsed)
+        }}
+      />
+      {invalid && <span className="pz-date-hint" role="status">{t('Une année (1950) ou une date (12/03/1950)')}</span>}
+    </span>
+  )
+}
diff --git a/frontend/src/components/PersonCard.css b/frontend/src/components/PersonCard.css
index 0946a70..591fd03 100644
--- a/frontend/src/components/PersonCard.css
+++ b/frontend/src/components/PersonCard.css
@@ -175,6 +175,10 @@
 .pc-label { flex: none; font: 400 13.5px var(--pz-sans); color: var(--pz-muted); }
 .pc-row .value { font: 400 14px/1.4 var(--pz-sans); color: var(--pz-ink); text-align: right; font-variant-numeric: tabular-nums; }
 .pc-row .pc-input { max-width: 62%; text-align: right; }
+/* Date : une année seule ou une date complète (issue #77), avec une aide si le texte n'en est pas une */
+.pc-row .pz-date { justify-items: end; max-width: 62%; }
+.pc-row .pz-date .pc-input { max-width: 100%; }
+.pc-row .pz-date-hint { text-align: right; }
 .pc-note { margin: 0; font: 400 italic 16px/1.5 var(--pz-serif); color: var(--pz-ink-2); white-space: pre-wrap; }
 
 .pc-alive {
diff --git a/frontend/src/components/PersonCard.jsx b/frontend/src/components/PersonCard.jsx
index 0e0c00a..58f0697 100644
--- a/frontend/src/components/PersonCard.jsx
+++ b/frontend/src/components/PersonCard.jsx
@@ -12,6 +12,8 @@ import './PersonCard.css'
 import PzBusy from './PzBusy.jsx'
 import { t, dateLocale } from '../i18n/index.js'
 import { formatPlace } from '../utils/place.js'
+import { isYearOnly } from '../utils/dateInput.js'
+import DateField from './DateField.jsx'
 
 const TYPE_LABELS = {
   photo: t('Photo'),
@@ -329,7 +331,9 @@ const PersonCard = ({
       if (union) {
         const p1 = persons.find(p => p.id === union.partner1Id)
         const p2 = persons.find(p => p.id === union.partner2Id)
-        return `${p1?.firstName || '?'} + ${p2?.firstName || '?'} (${unionTypeLabel(union.unionType)})`
+        // Union sans type (fréquent après un import GEDCOM) : pas de « (null) » à côté des prénoms
+        const kind = union.unionType ? ` (${unionTypeLabel(union.unionType)})` : ''
+        return `${p1?.firstName || '?'} + ${p2?.firstName || '?'}${kind}`
       }
     }
 
@@ -363,14 +367,26 @@ const PersonCard = ({
   }
 
   // Rendu d'un champ éditable ou lecture seule
-  const renderEditableValue = ({ field, value, placeholder, type = 'text', format = null }) => {
+  const renderEditableValue = ({ field, value, placeholder, type = 'text', format = null, emptyLabel = '-' }) => {
     if (!editMode) {
       const isEmptyValue = value === null || value === undefined || value === ''
-      // Une date complète se lit « 22 octobre 1928 », pas « 1928-10-22 »
-      const shown = type === 'date' && /^\d{4}-\d{2}-\d{2}/.test(String(value))
-        ? new Date(`${String(value).slice(0, 10)}T00:00:00Z`).toLocaleDateString(dateLocale, { day: 'numeric', month: 'long', year: 'numeric', timeZone: 'UTC' })
-        : format ? format(value) : value
-      return <span className="value">{isEmptyValue ? '-' : shown}</span>
+      // Une date complète se lit « 22 octobre 1928 », une année seule « 1928 », pas « 1 janvier 1928 »
+      let shown = format ? format(value) : value
+      if (type === 'date' && isYearOnly(value)) shown = String(value).slice(0, 4)
+      else if (type === 'date' && /^\d{4}-\d{2}-\d{2}/.test(String(value))) {
+        shown = new Date(`${String(value).slice(0, 10)}T00:00:00Z`).toLocaleDateString(dateLocale, { day: 'numeric', month: 'long', year: 'numeric', timeZone: 'UTC' })
+      }
+      return <span className="value">{isEmptyValue ? emptyLabel : shown}</span>
+    }
+    if (type === 'date') {
+      return (
+        <DateField
+          key={`${person.id}-${field}`}
+          className="pc-input value--editable"
+          value={getEditValue(field, value)}
+          onChange={(next) => handleFieldChange(field, next)}
+        />
+      )
     }
     return (
       <input
@@ -395,7 +411,7 @@ const PersonCard = ({
     const died = person.deathYear || (person.deathDate ? String(person.deathDate).slice(0, 4) : '')
     const parts = []
     if (born) parts.push(`${born}${person.birthPlace ? `, ${formatPlace(person.birthPlace)}` : ''}`)
-    if (!person.isAlive && died) parts.push(died)
+    if (!person.isAlive) parts.push(died || '?')
     return parts.join(' – ')
   })()
   const ageLabel = age === null ? null : person.isAlive ? t('{age} ans', { age }) : t('{age} ans au décès', { age })
@@ -697,7 +713,7 @@ const PersonCard = ({
                 {(!getEditValue('isAlive', person.isAlive) || (!editMode && !person.isAlive)) && (
                   <div className="pc-row">
                     <span className="pc-label">{t('Décès')}</span>
-                    {renderEditableValue({ field: 'deathYear', value: person.deathDate || person.deathYear || '', placeholder: t('Date de décès'), type: 'date' })}
+                    {renderEditableValue({ field: 'deathYear', value: person.deathDate || person.deathYear || '', placeholder: t('Date de décès'), type: 'date', emptyLabel: t('Date inconnue') })}
                   </div>
                 )}
                 {!editMode && (
diff --git a/frontend/src/components/galaxy/renderers.js b/frontend/src/components/galaxy/renderers.js
index 68f41d2..25b52ce 100644
--- a/frontend/src/components/galaxy/renderers.js
+++ b/frontend/src/components/galaxy/renderers.js
@@ -615,7 +615,9 @@ function drawPersonNode(ctx, node, pos, nodeProgress, {
     ctx.font = '400 11px "DM Sans", system-ui, sans-serif'
     ctx.fillStyle = COLORS.textLight
     const birthYearLabel = person.birthYear ?? '-'
-    const years = person.deathYear ? `${birthYearLabel}–${person.deathYear}` : `${birthYearLabel}`
+    const years = person.deathYear
+      ? `${birthYearLabel}–${person.deathYear}`
+      : person.isAlive === false ? `${birthYearLabel}–?` : `${birthYearLabel}`
     ctx.fillText(years, 0, 15)
   }
 
diff --git a/frontend/src/data/mockData.js b/frontend/src/data/mockData.js
index 3ccf6f9..90e0f62 100644
--- a/frontend/src/data/mockData.js
+++ b/frontend/src/data/mockData.js
@@ -107,7 +107,9 @@ function mapRemotePersonToLocal(person, current = null) {
     birthDate: person?.birthDate || current?.birthDate || null,
     deathDate: person?.deathDate || current?.deathDate || null,
     deathYear,
-    isAlive: !deathYear,
+    // Décédé(e) sans date connue (issue #77)
+    isDeceased: Boolean(person?.isDeceased) && !deathYear,
+    isAlive: !deathYear && !person?.isDeceased,
     frameType: current?.frameType || pickFrameType(person?.id),
     note: person?.notes || null,
     birthPlace: person?.birthPlace || null,
diff --git a/frontend/src/i18n/en/fiche.js b/frontend/src/i18n/en/fiche.js
index 732dc12..4ee3043 100644
--- a/frontend/src/i18n/en/fiche.js
+++ b/frontend/src/i18n/en/fiche.js
@@ -397,4 +397,10 @@ export default {
   'Souvenirs de {name}': 'Memories of {name}',
   'Une photo, une vidéo, un enregistrement ou un document, comme un acte en PDF. Ils rejoignent aussi ses souvenirs.': 'A photo, a video, a recording or a document, such as a record as a PDF. They also join their memories.',
   'Merci, c’est envoyé. Le moment apparaîtra dans sa vie quand la personne qui gère l’arbre l’aura accepté.': 'Thanks, it has been sent. The moment will show in their life once the person who manages the tree has accepted it.',
+  // Dates : année seule, décès sans date (issue #77)
+  'Année ou date': 'Year or date',
+  'Une année (1950) ou une date (12/03/1950)': 'A year (1950) or a date (12/03/1950)',
+  'Date inconnue': 'Date unknown',
+  'date inconnue': 'date unknown',
+  'Décédé(e), date inconnue': 'Deceased, date unknown',
 }
diff --git a/frontend/src/styles/pz.css b/frontend/src/styles/pz.css
index e73758e..d62a4b2 100644
--- a/frontend/src/styles/pz.css
+++ b/frontend/src/styles/pz.css
@@ -92,6 +92,10 @@ p, li, blockquote, figcaption, dd, .pz-sub, .pz-small, .pz-hint, .pz-error, .pz-
   transition: border-color 160ms ease, box-shadow 160ms ease; appearance: none;
 }
 .pz-field textarea { min-height: 96px; resize: vertical; }
+/* Champ de date : une année seule ou une date complète (DateField) */
+.pz-date { display: grid; align-content: start; gap: 4px; min-width: 0; }
+.pz-date input[aria-invalid="true"] { border-color: var(--pz-a500); }
+.pz-date-hint { font: 400 12px/1.35 var(--pz-sans); color: var(--pz-a700); }
 .pz-input::placeholder, .pz-field input::placeholder, .pz-field textarea::placeholder { color: var(--pz-faint); }
 .pz-input:focus, .pz-field input:focus, .pz-field textarea:focus, .pz-field select:focus {
   outline: none; border-color: var(--pz-a500); box-shadow: 0 0 0 3px var(--pz-a100);
diff --git a/frontend/src/utils/dateInput.js b/frontend/src/utils/dateInput.js
new file mode 100644
index 0000000..98b68d1
--- /dev/null
+++ b/frontend/src/utils/dateInput.js
@@ -0,0 +1,38 @@
+// Saisie d'une date dans la fiche : une année seule (« 1950 ») ou une date complète (« 12/03/1950 »).
+// L'année seule se range au 1er janvier, la convention de toute l'appli (issue #77).
+
+const pad = (n) => String(n).padStart(2, '0')
+
+// Valeur stockée (« 1950-01-01 », « 1950 », « 1950-03-12 ») vers le texte du champ
+export function dateToInputText(value) {
+  const raw = String(value ?? '').trim()
+  if (!raw) return ''
+  const full = raw.match(/^(\d{4})-(\d{2})-(\d{2})/)
+  if (full) return full[2] === '01' && full[3] === '01' ? full[1] : `${full[3]}/${full[2]}/${full[1]}`
+  const year = raw.match(/^(\d{4})$/)
+  return year ? year[1] : raw
+}
+
+// Texte du champ vers la valeur stockée : '' si vide, « AAAA-MM-JJ » si valable, undefined si on ne comprend pas
+export function parseDateInput(text) {
+  const raw = String(text ?? '').trim()
+  if (!raw) return ''
+  if (/^\d{4}$/.test(raw)) return `${raw}-01-01`
+  let day
+  let month
+  let year
+  const dmy = raw.match(/^(\d{1,2})[/.\-\s](\d{1,2})[/.\-\s](\d{4})$/)
+  const iso = raw.match(/^(\d{4})-(\d{2})-(\d{2})$/)
+  if (dmy) [, day, month, year] = dmy
+  else if (iso) [, year, month, day] = iso
+  else return undefined
+  const d = Number(day)
+  const m = Number(month)
+  const y = Number(year)
+  const date = new Date(Date.UTC(y, m - 1, d))
+  if (date.getUTCFullYear() !== y || date.getUTCMonth() !== m - 1 || date.getUTCDate() !== d) return undefined
+  return `${year}-${pad(m)}-${pad(d)}`
+}
+
+// Une année seule (rangée au 1er janvier) se lit « 1950 », pas « 1 janvier 1950 »
+export const isYearOnly = (value) => /^\d{4}(-01-01)?$/.test(String(value ?? '').slice(0, 10))
diff --git a/frontend/src/utils/dateInput.test.js b/frontend/src/utils/dateInput.test.js
new file mode 100644
index 0000000..e0a0b8f
--- /dev/null
+++ b/frontend/src/utils/dateInput.test.js
@@ -0,0 +1,26 @@
+import { describe, expect, it } from 'vitest'
+import { dateToInputText, isYearOnly, parseDateInput } from './dateInput.js'
+
+describe('saisie d’une date (issue #77)', () => {
+  it('une année seule ou une date complète', () => {
+    expect(parseDateInput('1950')).toBe('1950-01-01')
+    expect(parseDateInput('12/03/1950')).toBe('1950-03-12')
+    expect(parseDateInput('2.3.1950')).toBe('1950-03-02')
+    expect(parseDateInput('1950-03-12')).toBe('1950-03-12')
+    expect(parseDateInput('  ')).toBe('')
+  })
+
+  it('refuse ce qui n’est pas une date', () => {
+    expect(parseDateInput('31/02/1950')).toBeUndefined()
+    expect(parseDateInput('195')).toBeUndefined()
+    expect(parseDateInput('vers 1950')).toBeUndefined()
+  })
+
+  it('réaffiche la valeur comme on l’a tapée', () => {
+    expect(dateToInputText('1950-01-01')).toBe('1950')
+    expect(dateToInputText('1950-03-12')).toBe('12/03/1950')
+    expect(dateToInputText(null)).toBe('')
+    expect(isYearOnly('1950-01-01')).toBe(true)
+    expect(isYearOnly('1950-03-12')).toBe(false)
+  })
+})
diff --git a/frontend/src/utils/lifeTimeline.js b/frontend/src/utils/lifeTimeline.js
index 862ff83..8457b20 100644
--- a/frontend/src/utils/lifeTimeline.js
+++ b/frontend/src/utils/lifeTimeline.js
@@ -193,13 +193,13 @@ export function buildLifeTimeline(person, family = {}, life = null) {
     if (within(year)) out.push({ key: `parent-death-${parent.id}`, year, order: 6, kind: 'fam', title: parentWord(parent) })
   }
 
-  if (deathYear) {
+  if (deathYear || person.isAlive === false) {
     const place = formatPlace(details.deathPlace || '')
     const extra = sourcesOf('death')
     out.push({
       key: 'death', year: deathYear, order: 9, kind: 'mile',
       title: place ? t('Décès à {place}', { place: place.split(',')[0] }) : t('Décès'),
-      meta: joinMeta(describeDate(person.deathDate, details.deathDateEnd, details.deathDatePrecision), ageAt(birthYear, deathYear)),
+      meta: deathYear ? joinMeta(describeDate(person.deathDate, details.deathDateEnd, details.deathDatePrecision), ageAt(birthYear, deathYear)) : t('date inconnue'),
       note: extra?.notes || '', sources: extra?.sources || '',
       ...milestoneFields(extra, { type: 'death' }),
     })
diff --git a/frontend/src/utils/lifeTimeline.test.js b/frontend/src/utils/lifeTimeline.test.js
index d36f156..a4b0105 100644
--- a/frontend/src/utils/lifeTimeline.test.js
+++ b/frontend/src/utils/lifeTimeline.test.js
@@ -61,6 +61,11 @@ describe('frise de vie', () => {
     expect(withMedia.find((e) => e.title === 'Maire').mediaIds).toEqual(['photo-1', 'photo-2'])
   })
 
+  it('décès sans date : le repère reste, en bas, « date inconnue » (issue #77)', () => {
+    const entries = buildLifeTimeline({ id: 1, firstName: 'X', birthYear: 1900, isAlive: false }, {}, null)
+    expect(entries.map((e) => [e.title, e.year, e.meta])).toEqual([['Naissance', 1900, ''], ['Décès', null, 'date inconnue']])
+  })
+
   it('dit les dates comme on les dit', () => {
     expect(describeDate('1879-01-01', null, 'about')).toBe('vers 1879')
     expect(describeDate('1879-01-01', null, 'before')).toBe('avant 1879')